Sachin is younger than Rahul by 4 years. If their ages are in the respective ratio of 7 : 9, how old is Sachin ?

\par Let Rahul's age be x years. Then, Sachin's age = (x -7) years

\frac{x-7}{x} = \frac{7}{9}

9x - 63 = 7x

2x = 63

x = 31.5

\par Hence, Sachin's age = (x - 7) = 24.5 years